This invention relates generally to a control system and, more particularly, to a control system to automate operations for wheel tractor scrapers.
Earth moving machinery and more particularly wheel tractor scrapers are complex machines which include a great deal of skill to operate in an efficient manner. This is mainly due to the many complex features that are provided with these machines.
By way of example, wheel tractor scrapers include a load carrying bowl which is used to payload material scraped from a ground surface. The load carrying bowl may be moved into many different positions by the use of hydraulic lifts. In addition, the wheel tractor scraper may include several loading gears, aprons and implements (such as, for example, elevators and augers) as well as moveable ejectors and scrapers. All of these features must be controlled by the operator within the tractor cab of the wheel tractor scraper.
In order to control these features, the operator must not only be well acquainted with the controls of the tractor cab, but must also be trained to use such controls in the most efficient and safest manner. That is, the operator must be trained to use the controls so that the features of the wheel tractor scraper work in a precise sequence and within design parameters. This ensures that the wheel tractor scraper is working in its intended manner. This training can be quite complex and time consuming.
For example, in order to properly use the wheel tractor scraper, the operator must be able to control the raising and lowering of the load carrying bowl, and more particularly must be able to accurately adjust the load carrying bowl in order to ensure that the cutting edge of the load carrying bowl is properly scraping the ground surface. In addition, the operator must know when and how to properly adjust the implements so that the loaded material is properly distributed within the load carrying bowl. Simultaneously, the operator must select a proper loading gear and implement appropriate speeds, as well as select many other variables. To make the operation even more complex, the operator must also drive the tractor which includes steering, transmission shifting, braking and the like during the operation of these other features.
In U.S. Pat. No. 3,762,076 to Eftefield issued on Oct. 2, 1973, a hoeing control scraper system is provided. In Eftefield, an electro-hydraulic circuit provides semi-automatic control of movements of the hoeing apron loading device. Several fluid motors provide apron movement and are actuated and stopped by electric signals originating in the control circuit. In this manner, the apron can be efficiently controlled by the Eftefield system, but the Eftefield system still requires the operator to manually control the many features of the wheel tractor scraper.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention a control system has a load control module, a haul control module associated with the load control module and an eject control module. The eject control module is associated with the load control module and the haul control module.
In another aspect of the invention a method for controlling operations of a wheel tractor scraper is provided. The method has the steps of providing initial preset values for operating the wheel tractor scraper. The method also has the steps of controlling a loading operation, a hauling operation and an ejecting operation using the initial preset values.
In still another aspect of the invention a wheel tractor scraper has a tractor mounted to a load carrying bowl. A hitch, cutting edge, moveable ejector, apron and material moving implement are also provided. A load control module, a haul control module and an eject control module control the wheel tractor scraper during a loading, hauling and ejecting operation.